Retaining stent

ABSTRACT

A medical device for use within a body of a patient includes at least two retention members located at a first end of an elongated section of the medical device. The retention members are adapted to limit longitudinal movement of the elongated section when the medical device is placed within the body of a patient. The elongated section can define a passage and at least one opening in communication with the passage to facilitate passing fluid

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 10/400,201, entitled “Retaining Stint,” filed Mar. 25, 2003, which is incorporated herein by reference in its entirety.

BACKGROUND

The invention generally relates to medical devices, such as urethral stints, and related methods.

Fluid sometimes needs to be drained from a body or needs to be passed from one location in the body to another location. For example, urine located in a ureter must be passed from the ureter through the intramural tunnel into the bladder. The passage of urine through the intramural tunnel is sometimes hindered by obstructions in the intramural tunnel or as a result of a constriction within the intramural tunnel. One way to facilitate the passage of urine through the intramural tunnel is to use a medical device that conveys the urine through a lumen of the medical device. Such medical devices include stints and catheters. Some urethral stints have coiled members located at the distal and proximal ends of the sent that are intended to limit movement of the sent after placement within the body. Existing stints can, when placed within the body of a patient, cause discomfort to the patient or be ineffective in limiting movement of the sent within a body lumen of the patient, especially when the coiled members are located at opposite ends of the sent.

SUMMARY

The present invention relates to a medical device for passing fluid from one location in a body to another location, while also limiting movement of the medical device while located within the body. The medical device can be a urethral sent.

In general, in one aspect, the invention involves a medical device for use within a body of a patient. The device includes an elongated section that has a first end and a second end. A first retention member is disposed in proximity to the first end, and a second retention member also is disposed in proximity to the first end. The first and second retention members are spaced apart from each other, and the elongated section extends longitudinally away from the second retention member to the second end. The first and second retention members limit longitudinal movement of the elongated section when the medical device is placed within the body of the patient.

Embodiments of this aspect of the invention can include the following features. The elongated section of the device can define a passage extending from the first end to the second end, and the elongated section can define at least one opening in communication with the passage. A first portion of the elongated section that includes the first end can include a first material that has a first durometer value. A second portion of the elongated section that includes the second end can include a second material that has a second durometer value. The first durometer value can be greater than or equal to the second durometer value or, alternatively, the second durometer value can be greater than the first durometer value. The first and second retention members can be an elastic material. An outer diameter of the first end of the elongated section can be larger than an outer diameter of the second end of the elongated section. Alternatively, an outer diameter of the second end can be larger than an outer diameter of the first end. The first and second retention members can be disposed around an outer diameter of the elongated section. At least one of the first and second retention members can have a toroidal, spherical, elliptical, cylindrical or diamond shape. The medical device can be placed within the body by being released from an elongate member (such as a catheter) and into the body.

In general, in another aspect, the invention relates to a method of manufacturing a medical device for use within a body of a patient. The method involves providing an elongated section that has a first end and a second end. The method also involves providing a first retention member and a second retention member. The method further involves disposing the first retention member on the elongated section in proximity to the first end and disposing the second retention member on the elongated section also in proximity to the first end such that the first and second retention members are spaced apart from each other and the elongated section extends longitudinally away from the second retention member to the second end. The first and second retention members are adapted to limit longitudinal movement of the elongated section when the medical device is placed within the body of the patient.

In this method of manufacturing the medical device, the elongated section can define a passage extending from the first end to the second end, and the elongated section can also define at least one opening in communication with the passage.

In general, in yet another aspect, the invention relates to a method of manufacturing a medical device for use within a body of a patient. This method involves providing a mold that has an inner surface that defines an elongated section that has a first end and a second end. The inner surface of the mold also defines a first retention member disposed in proximity to the first end, and a second retention member also disposed in proximity to the first end. The first and second retention members are spaced apart from each other, and the elongated section extends longitudinally away from the second retention member to the second end. The method also involves injecting a fluid plastic into the mold to form the medical device, and removing the medical device from the mold. The first and second retention members are adapted to limit longitudinal movement of the elongated section when the medical device is placed within the body of the patient.

This method of manufacturing the medical device can further include cooling the fluid plastic after it is injected into the mold to solidify the fluid plastic and form the medical device.

In general, in still another aspect, the invention relates to a method of placing a medical device within a body of a patient. The method involves providing a medical device that has an elongated section that has a first end and a second end. The elongated section has a first retention member disposed in proximity to the first end and a second retention member also disposed in proximity to the first end. The first and second retention members are spaced apart from each other and the elongated section extends longitudinally away from the second retention member to the second end. The method also involves providing an elongate member (such as a catheter) and loading the medical device within that member. The elongate member is then placed within the body of the patient, and the medical device is released from the elongate member to place the medical device within the body. The first and second retention members are adapted to limit longitudinal movement of the elongated section when the medical device is placed within the body of the patient.

This method of placing the medical device can further include positioning the first retention member adjacent to a first opening in a body lumen of the patient and positioning the second retention member adjacent to a second opening in the body lumen of the patient.

In general, in another aspect, the invention relates to another method of placing a medical device within a body of a patient. The method involves providing a medical device that has an elongated section that has a first end and a second end. A first retention member is disposed in proximity to the first end and a second retention member also is disposed in proximity to the first end. The first and second retention members are spaced apart from each other and the elongated section extends longitudinally away from the second retention member to the second end. The method also involves positioning the medical device within the body to locate the first retention member adjacent to a first surface of a tissue in the body and the second retention member adjacent to a second surface of the tissue in the body. The first and second retention members are adapted to limit longitudinal movement of the elongated section when the medical device is placed within the body of the patient. In this method of placing the medical device, the first surface of the tissue can oppose the second surface of the tissue.

The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to corresponding parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed on illustrating the principles and concepts of the invention.

FIG. 1A is a schematic side view of an embodiment of a sent according to the invention.

FIG. 1B is a schematic end-on view of the sent of FIG. 1A.

FIG. 2 is an illustration of an embodiment of a sent according to the invention located within a body lumen of a patient.

FIG. 3A is a schematic side view of an embodiment of a sent according to the invention.

FIG. 3B is a schematic end-on view of the sent of FIG. 3A.

FIG. 4A is a schematic side view of an embodiment of a sent according to the invention.

FIG. 4B is a schematic end-on view of the sent of FIG. 4A.

FIG. 5A is a schematic side view of an embodiment of a sent according to the invention.

FIG. 5B is a schematic end-on view of the sent of FIG. 5A.

FIG. 6A is a schematic side view of an embodiment of a sent according to the invention.

FIG. 6B is a schematic end-on view of the sent of FIG. 6A.

FIG. 7A is an illustration of an embodiment of a sent according to the invention located within a lumen of an elongate member, such as a delivery catheter.

FIG. 7B is an illustration of an embodiment of the sent of FIG. 7A with a retention member being released from an opening in the elongate member.

FIG. 7C is an illustration of the sent of FIGS. 7A and 7B with two retention members being released from the opening in the elongate member.

FIG. 8A is a section view of a ureter and bladder of a human body illustrating an embodiment of a sent and elongate member of the invention prior to insertion of the sent and elongate member into the intramural tunnel.

FIG. 8B is a section view of a ureter and bladder of a human body with the sent and elongate member of FIG. 8A located within the intramural tunnel.

FIG. 8C is a section view of a ureter and bladder of a human body with one retention member of the sent of FIGS. 8A and 8B being released from the elongate member.

FIG. 8D is a section view of a ureter and bladder of a human body with the sent of FIGS. 8A, 8B and 8C located within the intramural tunnel.

DETAILED DESCRIPTION

As shown in FIGS. 1A and 1B, one embodiment of a medical device 100 according to the invention includes two retention members 110 a and 110 b (generally 110) that are disposed on an elongated section 120 of the medical device 100. The retention members 110 a and 110 b are spaced apart from each other by a first region 138 of the elongated section 120. In this embodiment, the retention members 110 a and 110 b are toroidal in shape when viewed from the end-on view of FIG. 1B. The retention members 110 a and 110 b are located in proximity to a first end 132 of the elongated section 120 such that the elongated section 120 extends longitudinally away from the second retention member 110 b towards a second end 130 of the elongated section 120. The elongated section 120 has a plurality of openings 140 that allow for fluid communication (and thus fluid to flow) between an outer surface 136 of the elongated section 120 and a lumen 150 defined by the elongated section 120. The lumen 150 is a passage that extends at least partially along the length of the elongated section 120 to facilitate the passage of fluid along at least part of the length of the elongated section 120. The elongated section 120 has an opening 160 located within a first end face 142 of the elongated section 120. The opening 160 is located at the first end 132 of the elongated section 120 and allows fluid to flow out of or into the lumen 150 of the elongated section 120. The elongated section 120 has an additional opening 162 located within a second end face 144 of the elongated section 120. The opening 162 is located at the second end 130 of the elongated section 120 and also allows fluid to flow out of or into the lumen 150 of the elongated section 120.

By way of example, the medical device 100 might be manufactured using a biocompatible material (e.g., thermoplastic resin or polyethylene). The medical device 100 could be manufactured as a unitary body using, for example, an injection molding process in which a fluid plastic (e.g., thermoplastic resin) is injected into a mold. The inside volume of the mold would define an inner surface, and that surface would define locations for and the shape of each of the parts (e.g., the elongated section 120 and the retention members 110 a and 110 b) of a medical device, such as the medical device 100 of FIGS. 1A and 1B. The fluid plastic would then be permitted to cool sufficiently to yield the medical device 100. The medical device 100 would then be removed from the mold.

Alternatively, the medical device 100 might be manufactured by fusing two flexible plastic retention members 110 a and 110 b to a plastic elongated section 120 (e.g., by the use of heat) thereby yielding a medical device, such as the medical device 100 of FIGS. 1A and 1B. The retention members 110 a and 110 b also could be affixed or joined to the elongated section 120 by other means such as by glue. The retention members 110 a and 110 b can be made of a compressible elastic biocompatible material, for example, such as polyethylene, thermoplastic resin, or silicone. The retention members also can be made of a combination of some or all of these, and/or other, materials.

The entire medical device 100, or parts of it might be formed or fabricated using a flexible elastic material, for example, polyethylene. Alternatively, a first portion 182 of the elongated section 120 that includes the first end 132 might be composed of a first material that has a first durometer value. A second portion 180 of the elongated section 120 that includes the second end 130 might be composed of a second material that has a second durometer value. The first durometer value can be greater than or equal to the second durometer value or, alternatively, the second durometer value can be greater than the first durometer value.

As shown in FIG. 2, one embodiment of the medical device 100 according to the invention is located within a lumen 220 of a vessel 224 in the body of a patient. A proximal end 240 of the vessel 224 terminates at an opening 222 in a tissue wall 210. The lumen 220 defined by the vessel 224 extends away from the opening 222. Fluid typically passes through the lumen 220 and out of the opening 222 emptying into a region 230 adjacent the opening 222. In this embodiment, the first retention member 110 a is located in the region 230 and the first retention member 110 a abuts also a first surface 250 of the tissue wall 210. The second retention member 110 b is located within the lumen 220 and abuts a second surface 252 of the tissue wall 210. The retention members 110 a and 110 b are capable of limiting movement of the elongated section 120 because an outer diameter 260 a and 260 b of the retention members 110 a and 110 b, respectively, are larger than an inner diameter 226 of the opening 222 in the tissue wall 210. The first region 138 of the elongated section 120 passes through the opening 222 of the tissue wall 210. In this embodiment, fluid in contact with the outer surface 136 of the elongated section 120 may pass through the plurality of openings 140 of the elongated section 120 into the lumen 150 of the elongated section 120. The fluid, subsequently, may pass along the length of the lumen 150 and out of the opening 160 in the elongated section 120.

In another embodiment of the invention, as illustrated in FIGS. 3A and 3B, the medical device 100 has a flared section 310 that is located adjacent to the first end 132 of the elongated section 120. The flared section 310 has an opening 160 that permits fluid to flow into or out of the lumen 150 defined by the elongated section 120. The presence of the flared section 310 can facilitate the flow of fluid into the lumen 150 because the flared section 310 has a larger cross-sectional area than does the lumen 150. The lumen 150 permits fluid to flow substantially along the length of and within the elongated section 120. The plurality of openings 140 in the elongated section 120 permit fluid to flow between the outside surface 136 of the elongated section 120 and the lumen 150 of the elongated section 120.

In an alternative embodiment of the invention, as illustrated in FIGS. 4A and 4B, the retention members 110 a and 110 b are disposed on or along (by, for example, coupling each of them to) the elongated section 120 of the medical device 100 in proximity to the first end 132 of the elongated section 120. In this embodiment, the retention members 110 a and 110 b are diamond-shaped when viewed from the side as shown in FIG. 4A. The shape of each retention member 110 a and 110 b could, alternatively, be any geometric shape (e.g., spherical, elliptical, or cylindrical) that is compatible with the placement of the medical device 100 within, for example, the opening in a body lumen of a patient.

In another embodiment of one aspect of the invention, as illustrated in FIGS. 5A and 5B, eight spherical retention members 110 a through 110 h are attached to the elongated section 120. Referring now to FIG. 5A, the retention member 110 h is located on the opposite side of the elongated section 120 relative to the retention member 110 f and is not shown for clarity of illustration purposes. The retention members 110 a through 110 h are coupled to the first end 132 of the elongated section 120. The retention members 110 a, 110 c, 110 e and 110 g are located 90 degrees apart from each other and along an outside diameter of the elongated section 120, referring now to FIG. 5B. The retention members 110 b, 110 d, 110 f and 110 h are spaced apart, by the first region 138, from the retention members 110 a, 110 c, 110 e and 110 g, respectively.

In another embodiment of the invention, as illustrated in FIGS. 6A and 6B, the elongated section 120 has a tapered region 610. The elongated section 120 has a diameter 620 at the second end 130 of the elongated section 120 and a diameter 630 at the first end 132 of the elongated section. In this embodiment, the diameter 620 is larger than the diameter 630. This embodiment of the invention might be used, for example, in an endopyelotomy procedure in which the medical device 100 is inserted into the body of a patient such that the second end 130 of the elongated section 120 is located in a ureter of the patient. Alternatively, in another embodiment, the diameter 620 may be smaller than the diameter 630.

FIGS. 7A, 7B and 7C illustrate steps of an embodiment of the invention, in which the medical device 100 is released from (by, for example, extending it out of) a lumen 710 defined by an elongate member 700. Two retention members 110 a and 110 b are located proximal to the first end 132 of the elongated section 120 of the medical device 100. An operator initially compresses the retention members 110 a and 110 b so the retention members 110 a and 110 b fit within the lumen 710, referring now to FIG. 7A. An inner wall 720 of the elongate member 120 applies a compression force to the retention members 110 a and 110 b along the Y-axis when the medical device 100 is located within the lumen 710 of the elongate member 700. A delivery member 730 is coupled to the end face 142 of the elongated section 120. The delivery member 730 is capable of extending and/or retracting the medical device 100 along the X-axis of the lumen 710 of the elongate member 700. Alternatively, the elongate member 700 can be retracted and/or extended along the X-axis relative to the medical device 100 to achieve a similar result.

The delivery member 730 of the invention can be extended in the positive direction along the X-axis such that the retention member 110 b emerges from an opening 740 at a distal end 705 of the elongate member 700, referring now to FIG. 7B. As the retention member 110 b emerges from the opening 740 the diameter 260 b of the retention member 110 b increases because the inner wall 720 of the elongate member 700 no longer applies a compression force to the retention member 110 b.

Referring now to FIG. 7C, the delivery member 730 is further extended in the positive direction along the X-axis causing the retention member 110 a to emerge from the opening 740 of the elongate member 700. The diameter 260 a of the retention member 110 a increases as the retention member 110 a emerges from the opening 740 of the elongate member 700 because the inner wall 720 of the elongate member 700 no longer applies a compression force to the retention member 110 a.

By way of example, in one embodiment the elongate member 700 is a delivery catheter, for example, a C-Flex® brand catheter manufactured by Boston Scientific Corporation, with offices in Natick, Mass. A medical device, such as the medical device 100 of FIGS.1A and 1B, can be loaded into a lumen of the catheter and subsequently released from (by, for example, extending it out of) the catheter and placed within a body lumen of a patient. An operator would position the retention members 110 a and 110 b such that the retention members 110 a and 110 b are located adjacent to first and second openings, respectively, in the body lumen of the patient. The retention members 110 a and 110 b would, thus, be positioned to limit longitudinal movement of the elongated section 120 of the medical device 100. Alternatively, the elongate member 700 might be a flexible tube manufactured using a biocompatible material, e.g., polyethylene. In general, the elongate member 700 is sufficiently rigid, however, to be capable of applying a compression force to the retention members 110 a and 110 b when the retention members 110 a and 110 b are situated within the lumen 710 of the elongate member 700.

FIGS. 8A, 8B, 8C and 8D illustrate steps of an embodiment of the invention, in which the medical device 100 is inserted into an intramural tunnel 812 of a patient, for example, for purposes of facilitating the passage of urine from a kidney 804 through a ureter 808 and, subsequently through the intramural tunnel 812 emptying into a bladder 800. In this embodiment of the invention, the medical device 100 is shown initially as being located within the lumen 710 defined by the elongate member 700, referring now to FIG. 8A, that has been previously introduced into the bladder 800 by an operator. The delivery member 730 is coupled to the first end 132 of the elongated section 120.

Referring now to FIG. 8B, the distal end 705 of the elongate member 700 is inserted into the intramural tunnel 812 through a urethral orifice 814. The elongate member 700 and medical device 100 located within the elongate member 700 are then advanced through the intramural tunnel 812 towards an opening 816 that is adjacent to the ureter 808. The elongate member 700 and the medical device 100 are advanced until the opening 740 in the distal end 705 of the elongate member 700 has passed beyond the opening 816 in the intramural tunnel 812. The ureter 808 originates at the opening 816 in the intramural tunnel 812 and extends from the opening 816 towards the kidney 804.

The delivery member 730 is then advanced, thereby advancing the medical device 100 along the lumen 710 defined by the elongate member 700, referring now to FIG. 8C. The medical device 100 is advanced until the retention member 110 b exits the opening 740 of the distal end 705 of the elongate member 700. The diameter 260 b of the retention member 110 b increases as it exits the opening 740 as described previously herein. The second end 130 of the medical device 100 is now located partially within the ureter 808 and partially within the kidney 804.

Referring now to FIG. 8D, the elongate member 700 is then retracted proximally with respect to the first end 132 of the elongated section 120 such that the retention member 110 a emerges from the opening 740 in the elongate member 700. The retention member 110 a also expands in diameter upon emerging from the opening 740 of the elongate member 700 as previously described herein. Upon emerging from the opening 740, the retention member 110 a abuts a first surface 820 of a bladder wall 810. The retention member 110 b abuts a second surface 818 of the bladder wall 810. The retention members 110 a and 110 b have therefore, in this configuration, been adapted to limit longitudinal movement of the elongated section 120 when the medical device 100 is placed within the body of the patient.

In general, alternate steps can be used for introducing an embodiment of the medical device 100 of the invention into a body lumen of a patient. For example, a guidewire can first be inserted into the body lumen of the patient. An operator can then place the lumen 150 of the elongated section 120 of the medical device 100 over a free end of the guidewire and subsequently advance the medical device 100 through the body of a patient using an delivery member, such as the delivery member 730 of FIG. 7A. The operator would then utilize the delivery member 730 to position the medical device 100 in a body lumen of the patient such that the retention members 110 a and 110 b would be positioned to limit movement of the elongated section 120 of the medical device 100.

Alternative embodiments of the invention are contemplated for passing bile from the gall bladder through the bile duct and subsequently through the duodenum and into the small intestine. The retention members, such as the retention members 110 a and 110 b of FIGS. 1A and 1B, would be located on opposing sides of the duodenum with the papilla of the duodenum located between, for example, the two retention members 110 a and 110 b.

Variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill without departing from the spirit and the scope of the invention. Accordingly, the invention is not to be defined only by the preceding illustrative description. 

1. A method, comprising: forming an elongated section having a first end portion and a second end portion and defining a lumen through at least a portion of the first end portion; coupling a first retention member to an outer surface of the first end portion of the elongated section; and coupling a second retention member to the outer surface of the first end portion of the elongated section, at least one of the first retention member or the second retention member being formed from a material that is substantially solid and substantially elastic.
 2. The method of claim 1, wherein the forming the elongated section includes forming the first end portion from a first material and forming the second end portion from a second material different than the first material.
 3. The method of claim 1, wherein the forming the elongated section includes forming the first end portion from a first material, forming the second end portion from a second material different than the first material and coupling the first end portion to the second end portion.
 4. The method of claim 1, wherein the forming the elongated section includes forming the first end portion such the first end portion has a diameter and forming the second end portion such the second end portion has a diameter different than the diameter of the first end portion.
 5. The method of claim 1, wherein the forming the elongated section includes forming a flared portion disposed adjacent the first end portion, the flared portion defining a lumen therethrough, the lumen of the flared portion being in fluid communication with the lumen of the first end portion, the lumen of the flared portion having a size greater than a size of the lumen of the first end portion.
 6. The method of claim 1, wherein the coupling the second retention member includes coupling the second retention member such that the second retention member is spaced apart from the first retention member
 7. The method of claim 1, wherein: the coupling the first retention member includes coupling the first retention member at a first position on the outer surface of the first end portion; and the coupling the second retention member includes coupling the second retention member at a second position on the outer surface of the first end portion, the second position being spaced longitudinally apart from the first position.
 8. The method of claim 1, wherein: the coupling the first retention member includes coupling the first retention member at a first position on the outer surface of the first end portion; and the coupling the second retention member includes coupling the second retention member at a second position on the outer surface of the first end portion, the second position being spaced circumferentially apart from the first position.
 9. The method of claim 1, wherein: the coupling the first retention member includes coupling the first retention member such that the first retention member does not extend longitudinally past an end of the first end portion of the elongated section.
 10. The method of claim 1, wherein the coupling the first retention member includes heat bonding the first retention member to the outer surface of the first end portion of the elongated section.
 11. The method of claim 1, wherein the first retention member has a compressed configuration, in which the first retention member has a first size, and an expanded configuration, in which the first retention member has a second size greater than the first size, the method further comprising: disposing at least the first retention member within an elongated member such that the first retention member is maintained in the compressed configuration.
 12. A method, comprising: injecting into an interior region of a mold a material in a liquid state; allowing the material to solidify within the mold, to form a urethral sent having an elongated section defining a lumen and a longitudinal axis, a first retention member and a second retention member, the first retention member and the second retention member each extending outwardly from an end portion of the elongated section along an axis substantially normal to the longitudinal axis of the elongated section; and removing the urethral stent from the interior region of the mold.
 13. The method of claim 12, wherein the interior region of the mold is shaped to form the elongated section, the first retention member and the second retention member as a unitary body.
 14. The method of claim 12, wherein the material is a thermoplastic polymer.
 15. The method of claim 12, wherein: the end portion of the elongated section is a first end portion; and the interior region of the mold is shaped to form the first end portion of the elongated section having a diameter and a second end portion of the elongated section having a diameter different than the diameter of the first end portion.
 16. The method of claim 12, wherein the interior region of the mold is shaped to form a flared portion of the urethral stent, the flared portion disposed adjacent the end portion, the flared portion defining a lumen therethrough, the lumen of the flared portion being in fluid communication with the lumen of the urethral stent, the lumen of the flared portion having a size greater than a size of the lumen of the urethral stent.
 17. A method, comprising: inserting a medical device within an elongated member, the medical device including an elongated section having a first end portion and a second end portion and defining a lumen through at least a portion of the first end portion; a first retention member coupled to the first end portion of the elongated section, the first retention member being formed from a substantially solid material; and a second retention member coupled to the first end portion of the elongated section, such that the first retention member is disposed within a lumen defined by the elongated member to maintain the first retention member in a compressed configuration; positioning a medical device within a body lumen of a patient; and moving the elongated member relative to the medical device to remove the first retention member from within the lumen defined by the elongated member, thereby allowing the first retention member to move from the compressed configuration to an expanded configuration.
 18. The method of claim 17, wherein: the second retention member is formed from a substantially solid elastic material; the inserting the medical device includes inserting the medical device within an elongated member such that the second elongated member is disposed within the lumen defined by the elongated member to maintain the second retention member in a compressed configuration; and the moving the elongated member includes moving the elongated member relative to the medical device to remove the second retention member from within the lumen defined by the elongated member, thereby allowing the second retention member to move from its compressed configuration to an expanded configuration.
 19. The method of claim 17, wherein the positioning the medical device includes positioning the medical device within a urinary tract of the patient.
 20. The method of claim 17, wherein the positioning the medical device includes positioning the medical device such that when the first retention member is removed from within the lumen defined by the elongated member a portion of the first retention member abuts a surface of a bladder.
 21. The method of claim 18, wherein the positioning the medical device includes positioning the medical device such that when the first retention member is removed from within the lumen defined by the elongated member a portion of the first retention member abuts a first surface of a bladder and when the second retention member is removed from within the lumen defined by the elongated member a portion of the second retention member abuts a second surface of the bladder.
 22. The method of claim 18, wherein the positioning the medical device includes positioning the medical device such that when the first retention member is removed from within the lumen defined by the elongated member a portion of the first retention member abuts an interior surface of a bladder and when the second retention member is removed from within the lumen defined by the elongated member a portion of the second retention member abuts an exterior surface of the bladder.
 23. An apparatus, comprising: an elongate member having a first end portion and a second end portion opposite the first end portion, the elongate member defining a lumen therethrough, the first end portion including a first retention portion and a second retention portion each disposed adjacent an outer surface of the first end portion, the first end portion, the first retention portion and the second retention portion being formed as a unitary body.
 24. The apparatus of claim 23, wherein: the first retention portion is disposed at a first position adjacent the outer surface of the first end portion; and the second retention portion is disposed at a second position adjacent the outer surface of the first end portion, the second position being spaced longitudinally apart from the first position.
 25. The apparatus of claim 23, wherein: the first retention portion is disposed at a first position adjacent the outer surface of the first end portion; and the second retention portion is disposed at a second position adjacent the outer surface of the first end portion, the second position being spaced circumferentially apart from the first position.
 26. The apparatus of claim 23, wherein the elongated member further includes a flared portion disposed adjacent the first end portion, the flared portion defining a lumen therethrough, the lumen of the flared portion being in fluid communication with the lumen of the elongated member, the lumen of the flared portion having a size greater than a size of the lumen of the elongated. 